[jira] [Commented] (CAMEL-11249) camel-core - Extend split() capabilities with pluggable splitters

["Nicola Ferraro (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/CAMEL-11249?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16017299#comment-16017299 ] 

Nicola Ferraro commented on CAMEL-11249:
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There's a limitation set by our own convention of putting a "SPLIT_COMPLETE" header (or also a "MULTICAST_COMPLETE" header) on the last element of the collection to be split.

If we want to extend splitting to asynchronous streams (like Flow/Publisher), that convention should be changed, because in a stream you know that the stream is finished when you receive a specific event. So when you emit an item, you know that it's the last if you receive (later) a stream close event... but you cannot wait indefinitely.

A dirty solution would be to process an element of the stream only when the subsequent event is received (that may be another element or the completion event).

Or.. introduce empty exchanges to signal such events?

> camel-core - Extend split() capabilities with pluggable splitters
> -----------------------------------------------------------------
>
>                 Key: CAMEL-11249
>                 URL: https://issues.apache.org/jira/browse/CAMEL-11249
>             Project: Camel
>          Issue Type: Improvement
>          Components: camel-core
>            Reporter: Nicola Ferraro
>            Assignee: Nicola Ferraro
>             Fix For: 2.20.0
>
>
> Currently a "split().body()" processor will work with a limited set of value types.
> This is an excerpt from ObjectHelper.createIterator(value):
> {code}
>      * Creates an iterator over the value if the value is a collection, an
>      * Object[], a String with values separated by comma,
>      * or a primitive type array; otherwise to simplify the caller's code,
>      * we just create a singleton collection iterator over a single value
>      * <p/>
>      * Will default use comma for String separating String values.
>      * This method does <b>not</b> allow empty values
> {code}
> New libraries (reactive-streams, grpc, but also java 8 collections) make heavy use of streams, not only standard java collections.
> In order to support a wide range of streams types, we can make the split algorithm pluggable, e.g. by providing custom conversions from a specific type to a "CamelStreamingObject" (tbd).
> This way we can convert any kind of streaming object (e.g. Publisher) into its content by putting a ".split().body()". 
> In Camel 2.19.0, users should include a "UnwrapStreamProcessor" in their routes to do this conversion.



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